iphone 17 pro- is ot a good idea to add camera lens protectors ?

Now I don't know which specific Spigen case you are using. But most Spigen cases have a slightly raised edge around the camera, so that the lenses don't come into contact with anything when you put it down, for example on a table.

I personally wouldn't put anything in front of the lens on my iPhone. But it won't damage your iPhone, you can however risk that the lens cover you put on may degrade your photos.

I would recommend watching some reviews of the lens cover you are considering buying on YouTube before you do so. Alternatively. If you are nervous about your new iPhone, you can consider Apple Care.

You can read more about Apple Care here:

Add AppleCare coverage to your Apple device - Apple Support

All the kens covers I’ve ever seen are of such poor optical quality that the photo quality suffers greatly. I’d never use them.